fix e2e tests for cgroups

pkg/util/runtime/cpu_linux.go

@@ -38,7 +38,7 @@ import (
 func NumCPU() int {
 	cpus := runtime.NumCPU()
 
-	cgroupVersion := getCgroupVersion()
+	cgroupVersion := GetCgroupVersion()
 	cpuQuota := int64(-1)
 	cpuPeriod := int64(-1)
 
@@ -60,7 +60,7 @@ func NumCPU() int {
 	return int(math.Ceil(float64(cpuQuota) / float64(cpuPeriod)))
 }
 
-func getCgroupVersion() int64 {
+func GetCgroupVersion() int64 {
 	// /sys/fs/cgroup/cgroup.controllers will not exist with cgroupsv1
 	if _, err := os.Stat("/sys/fs/cgroup/cgroup.controllers"); err == nil {
 		return 2

test/e2e/cgroups/cgroups_linux.go

@@ -0,0 +1,97 @@
+//go:build linux
+// +build linux
+
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cgroups
+
+import (
+	"log"
+	"os"
+
+	"github.com/onsi/ginkgo/v2"
+	"github.com/stretchr/testify/assert"
+
+	"k8s.io/ingress-nginx/test/e2e/framework"
+
+	"path/filepath"
+	"k8s.io/ingress-nginx/pkg/util/runtime"
+
+	libcontainercgroups "github.com/opencontainers/runc/libcontainer/cgroups"
+)
+
+var _ = framework.IngressNginxDescribeSerial("[CGroups] cgroups", func() {
+	f := framework.NewDefaultFramework("cgroups")
+
+	ginkgo.BeforeEach(func() {
+		f.NewEchoDeployment()
+		f.NewSlowEchoDeployment()
+	})
+
+	ginkgo.It("detects cgroups version v1", func() {
+		cgroupPath, err := libcontainercgroups.FindCgroupMountpoint("", "cpu")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		quotaFile, err := os.Create(filepath.Join(cgroupPath,"cpu.cfs_quota_us"))
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		periodFile, err := os.Create(filepath.Join(cgroupPath,"cpu.cfs_period_us"))
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		quotaFile.WriteString("4");
+		quotaFile.Sync();
+
+		periodFile.WriteString("2");
+		periodFile.Sync();
+		
+		assert.Equal(ginkgo.GinkgoT(), runtime.GetCgroupVersion(), int64(1))	
+		assert.Equal(ginkgo.GinkgoT(), runtime.NumCPU(), 2)
+
+		os.Remove(filepath.Join(cgroupPath,"cpu.cfs_quota_us"))
+		os.Remove(filepath.Join(cgroupPath,"cpu.cfs_period_us"))
+	})
+
+	ginkgo.It("detect cgroups version v2", func() {
+		if err := os.MkdirAll("/sys/fs/cgroup/", os.ModePerm); err != nil {
+			log.Fatal(err)
+		}
+
+		os.Create("/sys/fs/cgroup/cgroup.controllers")
+		file, err := os.Create("/sys/fs/cgroup/cpu.max")
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		file.WriteString("4 2");
+		file.Sync();
+		
+		assert.Equal(ginkgo.GinkgoT(), runtime.GetCgroupVersion(), int64(2))	
+		assert.Equal(ginkgo.GinkgoT(), runtime.NumCPU(), 2)
+
+		os.Remove("/sys/fs/cgroup/cpu.max")
+		os.Remove("/sys/fs/cgroup/cgroup.controllers")
+	})
+})